1. Field of the Invention
The present invention relates to a vertical junction field effect transistor having epitaxial gate layers in a trench surrounding a vertical channel region, and methods of making such devices.
2. Background
MOSFET based power switches generally have low reliability due to gate oxide failure, and also possess high forward voltage drop. Vertical junction field effect transistors (VJFETs) typically provide more efficient power control without the problems associated with MOSFETs. However, VJFETs have high on-state resistance. Short-channel VJFETs are known to provide lower on-state resistance, but typically require high turn-off voltage. There is thus a need to provide an improved VJFET that can be more easily turned off and that has lower on-state resistance.